Insulin might not be so great after all…

...well, for fish anyway.
Insulin is widely known as the hormone used to treat diabetic sufferers. It is responsible for countering the effects of another hormone, called glucagon, to restore blood sugar levels within a number of animal species.

Until recently, insulin’s affiliation with murder was only seen through fiction. However, a team in Salt Lake City has now proved that this might not be as fictional as first thought.

Certain types of mollusc, known as cone snails, have been found to use insulin as one of their many weapons to capture fish. The snails that use this technique – Conus geographus and Conus tulipa ­– release a cocktail of toxins, including insulin, into the water to confuse and weaken the fish. This then causes the fish to go into hypoglycaemic shock and allow the snail to ingest the fish whole.

The insulin used by the snails differs in structure to the insulin inside our bodies. In fact, it is the smallest insulin molecule ever found by scientists before. However, this small size is thought to explain why it it’s so fast and effective in deactivating the fish’s movement.

The team behind the work were very shocked by the findings. Safavi-Hemami, the leading researcher, said, "It was very surprising to us since it had never been shown before and people have worked on animal venoms for decades."

They now plan on investigating the genetic make up of the insulin produced by the snails. This would determine whether they developed the weaponised insulin from scratch or evolved it from their own insulin.

Safavi-Hemami stated, "It's believed that vertebrate insulins have evolved from ancestral invertebrate genes. Whether this is also true for the insulin we found cannot be answered yet."